Solar energy is considered by many to be the energy of the future. A recent survey was taken to compare the cost of solar energy to the cost of gas or electric energy. Results of the survey revealed that the distribution of the amount of the monthly utility bill of a 3-bedroom house using gas or electric energy had a mean of $101 and a standard deviation of $10. If the distribution is normal, what percentage of homes will have a monthly utility bill of more than $91?



Answer :

Answer:

84.1%

Step-by-step explanation:

as seen in the image, the centre of the normal distribution is $101. from here, subtracting 1 standard deviation would take us to $91 (the amount given in the question).

standard deviations have set percentage values (see image 2). $91 occurs at - 1 standard deviation so all percentages above this pay more than $91 for their monthly utility bill.

right of the mean is 50% then an additional 34.1% above the $91 (see image)

50% + 34.1% = 84.1%

this is a little confusing but i hope this makes some sense :) let me know if theres anything i can clarify

View image esthergaia
View image esthergaia